Counterbore



S p 1930. Q A. 1.. GEITNER COUNTERBORE Filed March 16, 1929 lnventoj A/cxqna/er L Gad/ver- Attorney Patented seen 23, I 1930 v T providea co-unterbore which is both.

counrnnnonn v Application filed March 16, 929. Serial No. 347 573.

tools andhas for its various objects simple and z:strong in construction. and in which theindividual cutters: may be 1nd1 vidually and? collectively adjusted "to com -.pensate for wear: I

j- To provide lockingimeans for each of the I cutters witlrwhich a'step by stepadjustment of the cutters in ithe body of, the 'counterbore To provide arcounterbore which the l separate cutters are jprovided with, a cutting v edge at right 'an les'to the axis "of rotation the full width-o the cutter'and with a cuttingledge parallel tojthe'axis of rotation ad- .j'acent to the right angleacutting' cdgealong a fraction of the length of the cutter;

To provideaguide slotfor each of the cuttersflof the 'counterbore ini' which the cutter may be 'adjustedyradiallyias well-as laterally t0 compensate fol'ma ny v a in of the 'll lll'jlng edges; p

* All these and other obj ects of thisinvention 'will 'be' apparent/from the accompanying drawing 'the specification and the appended claimsforming a part-thereof.

we f Figure dis a detail sectional view ofa por- @In the accompanying drawing :ff g Figure 1 is a 's'ide' elevationof the complete counterbore rpartial'ly broken away;

Figure Zis an end elevation of the countertion o f the counterho're illustrating one of the locking nieans1for iclan p1nga cutter in place 1 in the head offjt-he cbunterbore5 thesection being taken 'on the line 3fv3 of Figure 1.

Figure 4 isa sectional view of the head of the counte'rbore illustrating a modified form o'fiholdingthe cutters in place therein.

v. Figure 5 isa side elevation of a portion of the head of the count'erbore illustrating another modified form of locking thelindividual cuttersinplacetherein. j. gure 6 is a partiallongitudinal sectional .viewfof th m d fi .f of the head iQ c hQWu tH'bore; g r

Figure 7 *is na verti'cil cross section of the ;;eounterbore illustrated in Figure 6, the see- This invention relates to counterboring tion being taken on the line 7 7. of Fig-' ure'6. i F a c Figure 8 isa side elevation of the cutter.

iThe counter-bore forming the subject mat ter 'ofmy present invention is an improvement over other counterboring tools on which I havesecured Letters Patent. The present PATENT I improvements consist mainly in the manner the front thereof. The shank 2 is integral with the head of the counterbore and while I have' shownit tapered, a straight shank may be provided instead. The pilot 3 is removable from the head and forithis purpose the center of 'the head 1 is drilled out to provide a longitudinal hole therein which is adapted to receive the shankv lof the pilot. As illustrated in Figure 1 the head 1 is drilled the full length of it and from the rear of the hole extends the duct .5 which leads angularly to the outside of the shank 2 of the coun terbore. The hole inthe head is thus open at both ends and this precludes any possibility of filling the hole in the head, as any substance lodged in the hole may be blown are shown in number, although larger or sinallernumbers of guide slots may be providedinstead. In each ofthe guide channels is mounted acutter 7 The guideslots extend in the body in an angular direction both in the vertical and the horizontal plane so that a movement of the cutter out ofits guide channelwill not only move the vertical or radial cutting edge forwardly of the head but will also move the short longitudinal cutting edge outwardly of the head. In

this xvay any Wear in both of-the cutting edge'sdue to the regrinding or these cutting q I edges im'ay. be snnultaneously compensated ior by a movement or the cutters outoi' th guide slots in the head the counter-bore" In the rormf of the counterhore' illustrated in Figure lrthe ad ustment of thecuttersin V the head is secured hy thering nut 8 which, v for this purpose, IS'tlllQEtClGd to the threaded,

rear portion or the head as illustratedin Figurel; The-rear end of allof'the" cutters '7 rest againstthe front face of the ring'nut sothat on threading the nut rorwardly on the head all of the-cutters are simultaneous;

ly forcedforwardly in the head with the ref s'ult above-described v A For thepurpose of clampingthecutters in place in their respective guide channels eachcutte'r s provided with a longitud nal w clamping screw doWnontothe eccentric Wash er thehead'o f the'screW forces the eccentric washer down into the pocket. i The overhang ing'portion of the eccentric washenivhiclr projectsinto the groove in the side or the cutter at the" same time'iorce's thec'utter in place in its guide channel Whenever the clamping screw is tightened against the Washer. The bottom of the groove in the cut ters isheveled and the overhanging portion ot the eccentric Washer 9 which extends into the groove is correspondingly beveled so that on the downward movement of the Washer the cutter is not only forced downwardly against the bottom of the guide channel'but'also outwardly against the side of the guide channel. The cutters 7, Tare thus adjustahly clamped in -place and held against radial movement in the head by meansof the clamp ing screws 11. 'llh e ring nut 8 on the other handserves to'hold the cutters against longitudinal movement in the head against the pressure exerted when the, cuttersare' forced I against theworkfi a V s V Counterhores have heretoforeheen used to face on the immediate areasurrounding an opening. The present tool is used'ror this same purpose but in addition isadapted to he usedror the purpose'of facing off acylinf drical surface surrounding the areaaround 1 'airopening. In this Way the Wall, asWe-ll as the end of a cylindrical pocket forming an ex tension of ahole, nay he finished off by means of the counterbore' illustrated and described.

-Theradial cutting edgesrormed at the outer ends ofthe cutters therull width thereof finishoff the end ofthe pocket or-the immediate. area surrounding the hole, While the longithe axisof rotation of the counterhore and I extends a short distance rearwardlyfromthe radial cuttingqedge,:finishes oficthe'wall of the pocket I I c a s 1n Figures nd 5 I have illustrated two modified nethods of holding the :cutters against endwi'se "movement: in their guide channels. In the method illustrated in Fig um dithe bottom of each cutter *is"provided With'a series of notches-20,20 which are suitably spaced either atregularorirregular intervals. 'The periphery ofa Washer 21 sur-- rounding the shank ofthe pilot and suitably i spacecl irom the rear of the pilot extends into one of thesenotchesf sothat when the [cutter is forced down-into its guide channel bythe clamping screW,,o ne ofthenotches, is also forced-in place'over thef then forms a shoulder "which serves to hold the cutter against endWise movement in the 'asher which guide channel. [The Washer is ilocatedkhe tween the pilot and, the end-otthe'headfindis 7 thus held fixed-against movement onthe shank ofthe pilot As the frontcuttingedgeof the 7' cutter is ground ibackiuntiil the first Qfihfl notches no longer can be engagedby the Wash er to'hold the cutter against inovementythe cutteris moved forwardin theiguide-chan neluntilthe next. notch engages the asher, Y

In this wayia step-:by stepflongitudinail ad- 7 justment may he:secured for the cutterivithout i the: use' of the ring nut illustrated in Figurelni r In. the; i'modification illustrated in Figure '5 the samejste-p by step longitudinal adjustment is secured bytproviding onetside of each cutter With-a 'series of grooVes'30,'30 begins ning atthe rear end thereof; Acorrespond ing grooveis provided in. the opposite'side i of the guide channel in-towhich the cutter is inserted so that the groove inthe channel andone of the groovesin the cutterprovide anppening into which the key pin 31 may he lnserted. The engagement'ofthe key pin in both the grooveiuthe side ofthechannel and the side .ofthe cutter, then holds thecutter against movement the guide channel thus dispensing with thering nut 81for, this" purpose lVhen, -tlie cutterfimusti.be' moved forwardly inthe guide channel the key i I is withdrawn to allow-the cutter to he. moved j longi u i a ly n thegii Jch nelun l th next groove in the side of thecutter is located opposite the groovein the channel ale lows the key pin to be inserted 1 between them. 7

figurestwo cutters 40iand ll areheld inplace in the head of the counterbore. The "bot- Themodification illustrated in Figures; 6 and 7 combines theadjuf tment provided by tom or inner cutter isnotch ed as described in connection With Figure4"and'isengaged h tudinal cutting edge, which is parallel {to by thewasher QO'Yfor thepurpose o'f hold in g ".itvjagainst endwise movement in the guide I channel. The upper or outerjcutter isbacked nut. 'yBoth cuttersiare clamped in place in the guide slot by ;a suitable clamping means such as are illustrated in F igure' 7 inwhich In this form of counterbore the cutting edge of the inner cutters is used to face off the immediate area surrounding, the hole, whilethe cutting edge of the outercutters finishes off in a predetermined form, dependingon the outline'of the'cuttin'g'edge, the

area adjacentto the area surrounding the hole. The adjustment securedby the ring nut also makes it possible to adjust theouter cutters independently of the inner cutters,

I claim:

A counterbore having a head with a shank at the rear of the head and a pilot at f the front of the head, said head having a plu- 'rality, of laterally angular guide channels i cut therein inclined upwardly from the rear 7 end of the head to the front end thereof, a cutter of uniform width and thickness mounted 7 an in each of saidinclined guide channels, a

- cutting edge, provided at the forward end of each of said cutters and disposedradially to the front end of said head, and a short cut- ,ting edge provided along the outer edge of each of. said cutters extending rearwardly of said'front cutting edge and at right angles thereto and at an angle to the top and bottom of the cutter.

2. A counterbore having a head with a shank at therear end and a pilot at the front end of the head, said head having a'plurality of cutters angularly mounted therein at an incline extending outwardly from the rear of the head, each of said cutters being of uniform width with-one cutting edge formed at the forward end thereof, a second cutting edge formed along the top of each of said out ters at right angles to the forward cutting edge and at an angle to the top and bottom of the-cutter and extending ,rearwardly from said forward cutting edge, each of said outters having a longitudinal groove in the side bottom, a washer extending into said groove,

" of saidcutters extending forwardly from the rear end and parallelto the bottom thereof, said groove having a downwardly inclined an inclined ledge on the under side of said washer and engaging said inclined bottom of said groove and means for forcing said washer downwardly to force said cutter downwardly and outwardly in said head.

7-3. A counterbore having a head with a shank at the rear and a pilot at the front,

a plurality of guide channels in said head,

a cutter located in each of said guide channels, a shoulder carried by said head behind its. pilot, a seriesv of notches in the bottom of said cutters adapted to individually engage over saidsh'oulder and means'for clamping V cutters against radial movement in said head. the upper cutter'is forced down upon the lower cutter by means 'of'the clamping screw and the eccentric washer 43.

4. Acounterbore having a head with a shankat'the rear and a pilot atthe front, a

plurality of guide channels in said head, cutters located in said guide channels, means provided at the bottom of said cutters and cooperating with said pilot to hold said cutters against endwise movement, means provided in said head and means provided in the side of said cutters and cooperating with the means in said head to hold said cutters against outward movement.

5. A counterbore having a head with a shank at therear and a pilot at the front,

a plurality of guide channelsin said head, a pair of cutters in each of said guide channels one on top of the other, means provided in the bottom of the inner cutters to hold said nner cutters against endwise movement in said guide channels and means carried by said head and engaging therear of said outer cutters to hold said outer cutters against endwise movement in said guide channels.

6. A counterbore having a head with a shank at the rear and a pilot at the front,

a plurality of guide channels in said head,

a pair of cutters in each of said guide channels one on top of the other, means provided in the bottom of the inner cutters to hold said inner cutters against endwise movement in said guide channels and means carried by said head and engaging the rear of said outer cutters to hold said outer cutters against endwise movement in said guide channels, and means for simultaneously clamping each pair of cutters in their respective guide channels and hold them against outward move ment therein. o

7. A counterbore having a head with a shankat the rear thereof, and an axial hole extending into the front end thereof, a pilot, a shank at the rear of said pilot adapted to engage into the axial hole in said head, means for clamping said shank of said pilot in place in said head, a washer carried by said pilot shank and spaced from therear of said pilot and held against the front of said head, a

plurality of cutters carried by said head, a 

